Study On Influence Of Stacking Project Onexisting Bridges At Deep Soft Soil Andcontrol Technology

Based on the analysis of the test results of a bridge in Fujian,this paper uses FLAC~3DD to study the effects of stacking project on the bridges in the deep soft soil and the control measures.The correctness of the numerical model is verified by comparing the test results with the calculation results.And use this model to analyze the displacement and bending moment of the bridge under different stacking factors.Finally,use the numerical model to study how to reduce the impact of the stacking project on the adjacent structure.The main contents and results of this paper are as follows:On-site inspection found that the distance between the bridge and the stacking project gradually increased,and some of the heaping soil is close to The edge of the pier;the measured line shape of the first joint beam is displaced to the right side of the line as compared with the design.It is found that through the numerical model that the overall deformation trend of the piles is the same at all stages of stacking.The displacement in the middle of the pile is large,and the displacement at both ends is small.The pile near the side of the stacking is more affected,and the displacement and bending moment are significantly larger than the pile far from the stacking side.The lateral displacement of the pile increases with the increase of the pile level.The displacement of beam’s trend calculated by the model is basically consistent with the trend of the actual test results.Deformation control measures under stacking project:Selecting the appropriate stacking method can effectively reduce the impact of the stacking.The isolation stress method is adopted,.This method uses both cement soil mixing pile and concrete mixing pile to reinforcement the area.The calculation shows that this method can effectively isolate the transmission of soil stress and greatly reduce the influence of the stacking project on the surrounding structure.Controlling the impact of stacking project on the structure from the source is the most effective method.Control the distance between the surcharge area and the structure,and the height of the stack.This scheme can be preferred when conditions permit.